Based on the COLTRIM established at IMP, we measured the state-selective differential cross sections for the He~(++) on He collisions at low incident energies. The scattering angle was obtained by reconstruc- tion of the vertical momenta of the recoil ions, and the state-selective information was measured by the re- Based on the COLTRIM established at IMP, we measured the state-selective differential cross sections for the He ~ (++) on He collisions at low incident energies. The scattering angle was obtained by reconstruc tion of the vertical momenta of the recoil ions , and the state-selective information was measured by the re-